Work and conservative forces

Suppose a force acts on an object. the force does not vary with time, nor with the position or velocity of the object. Start with the general definition of work done by force, and show that the force is conservative

Suppose a force acts on an object. the force does not vary with time, nor with the position or velocity of the object. Start with the general definition of work done by force, and show that the force is conversation.

3. The attempt at a solution
I started with W = FX
W = E final - E initial
E = KE f + PE f - KE i - PE i
W = 0 + PE f - O - PE i Since KE is a non-conservation force and there is only a conservative force.

This line not true. Saying that KE is a non-conservative force is not true.

I would suggest you start with some definitions. What is the general formula for the work done by a force? And also, what is the definition of a conservative force?